This is an EarthCache and has special requirements for logging it. You cannot log a Found It without responding to the logging requirements set out below.
Only one find claim per Message. Each Geocacher claiming a find must submit an individual response. One team can not lodge a response on behalf of a group of people.
A volcanic plug is a landform created when volcanic magma hardens inside a vent on an active volcano. They are sometimes called volcanic necks or puys. The plug is revealed when the surrounding land is eroded.
The plug is usually harder than the surrounding rock. If a plug is preserved, erosion may remove the surrounding rock while the erosion-resistant plug remains. This is what produces the distinctive upstanding landform.
BUT, is Mt Lindesay a Volcanic Plug? It certainly looks like one.
Apparently not! There is a much bigger picture here. Yes, Mt Lindesay is remarkable for its tiered summit, but it is the eroded remnant of lava flows from the nearby Focal Peak shield volcano.
According to a different Rod (one who has tertiary qualifications in earth science),
Mount Lindesay gets its shape by the rhyolite that forms the topmost layer. The rhyolite is hard, resistant to weathering and therefore remains relatively difficult to erode. It is for this reason that the rhyolite has protected the underlying softer rock at Mount Lindsay [sic] and you can see the same process for ridges to the east and south of the mountain too. The actual vents for the rhyolite and underlying basalt lavas is actually a little tricky to definitely locate but we do know that the main volcanic centre for these rocks was at the Focal Peak Volcano located in the vicinity of present-day Mount Barney a significant distance to the north.
Rhyolite is a felsic [relating to or denoting a group of light-coloured minerals] extrusive [in which hot magma from inside the Earth flows out (extrudes) onto the surface as lava] rock. Due to the high silica content, rhyolite lava is very viscous. It flows slowly, like toothpaste squeezed out of a tube, and tends to pile up and form lava domes.
According to the article MOUNT BARNEY - MOUNT BALLOW by Neville Stevens and Warwick Willmott
The prominent cliffs of Mount Lindesay, and of Mount Glennie farther east, are remnants of horizontal rhyolite lava flows of the Mount Gillies Volcanics (probably erupted from Mount Gillies), which have subsequently been isolated by erosion (Mount Lindesay is NOT a volcanic plug).
The above article gives a fascinating overview of how this part of South East Queensland came into being - events that were far greater than the Mount Warning/Tweed Caldera which is more prominent and highly visible.
To log a find for this earth cache, you ar required to view Mt Lindesay from two different locations, and then answer the question posed below.
WP1: S 28° 20.214' E 152° 42.018' - at the border crossing - near the fence gate above the monuments and opposite the sheds. Mt Lindesay is 2.3K away
1. What two geological forces (a) created Mt Lindesay and (b) have given it its present shape?
2. Take of photo of yourself OR your GPS in front of the Mount Lindesay sign. Include it in your message, but please do not post it in your log, it might give too much away.
WP2: S 28° 19.605' E 152° 44.512' - at a safe spot to park lower down the QLD side of the Mt Lindesay Highway. You are now in a direct line between Mt Lindesay and Mt Gillies (roughly north-south).
3. What has happened to the horizontal rhyolite lava flow from Mt Gillies to Mt Lindesay?
For a different perspective on Mt Lindesay, take a look at the Google satellite image.
When you have your response to the above questions, please, if possible, MESSAGE us, using the link at the top of the page underneath the name of the Cache. We prefer the MESSAGE method, as apparently, we don't respond to emails very well, but messages we do. We will contact you by MESSAGE once your MESSAGE has been received. But you can log your find in the meantime, and just say that you have MESSAGED your answers to the COs.
Happy Earthcaching!
Oh, and don't forget to find the Tradition cache here, too: Collins Pass